DESCRIPTION: Prostate cancer is serious, 44 thousand men die of it in the United States per year, the second leading cause of death. But understanding and applying prostate cancer information is difficult for patients: The information is often difficult to understand, it changes rapidly, there is conflicting medical opinion about treatment, and the choices are often unattractive. We believe that if patients could practice applying prostate cancer information to realistic cases, this difficulty would be greatly reduced. We propose to use epidemiological data to build a computer-based simulation system chat patients could use for such practice, and to compare it to best current practice in computer-based information delivery, specifically that provided by the NCI-sponsored PDQ Web site. Our test protocol will focus on patients' ability to interpret prostate cancer information and form medically-appropriate intentions. Simulation has been unusually successful in other complex education and training domains. We believe it can be applied effectively to prostate cancer patient education. If measurably better results in patient reasoning are obtained, the utility of applying high-quality simulation to patient education is confirmed and the feasibility of expanding the work into a commercial product is supported.